--TEST--
Bug #71539.4 (Memory error on $arr[$a] =& $arr[$b] if RHS rehashes)
--FILE--
<?php
$array = [0=>[]];
$array[0][0] =& $array[0][''];
$array[0][0] = 42;
var_dump($array);
?>
--EXPECT--
array(1) {
  [0]=>
  array(2) {
    [""]=>
    &int(42)
    [0]=>
    &int(42)
  }
}